Writing tends to start with a overall premise. Because writing can’t be arbitrary, you’re going to want to lock down what you’re going to be writing about, the the theme you’re going to be exploring, and you’re going to want to have some sense of how you’re going to make it interesting.

Hence the premise test: An (ADJECTIVE) (ARCHETYPE) must (GOAL) or else (STAKES by (DOING) and learns (THEME) .

Hypothetical Original Example: A cowardly knight must save a spoiled prince from a dragon, or else the realm will fall into war. He must cross the bleak desert, tame a flock of eagles, and fight through a fraternity of ogres. He overcomes his cowardice and learns that the measure of a man is in his deeds, not his words.

Commercial example (Speed) A driven cop is trapped on a speeding bus that will explode if it slows below 50 MPH. He must find a way to disarm the bomb, save the passengers, and stop the madman and learns little, but is rewarded for his grit and for sticking to his guns. Good conquers evil.

Art House Example (Boyhood) A young boy with a poetic soul must navigate through his complicated boyhood, or else lose his individuality. We follow him through formative events that occur over 12 years of his life, and in the the process, he learns how to trust himself and be self sufficient.

The more complete your “doing” section is, the more robust your movie idea. Take a look at these examples. If you didn’t know what they were, you wouldn’t be sold on them. Not until the visceral details of the second act were communicated to you.

A self destructive piano genius must resolve his issues re his estranged father or else continue his downward spiral. He does this by (events of the movie) and learns that his efforts to normalize or resolve his life are doomed to fail. Hence he continues his drifter lifestyle. (Five Easy Pieces)

A desperate man robs a bank to pay for his lover’s sex change operation, but a hostage situation ensues. He must escape it or else go to jail. He does this by (events of the movie). He fails, and learns that his failings (carelessness and desperation) have doomed him in crime just as they’ve doomed him in all other areas of his life. (Dog Day Afternoon)

A group of criminals (and one undercover cop) pull off a robbery, but have to hide from the heat. They quickly turn on each other and do (events of the movie) in the process leaning that their line of work precludes trust. (Reservoir Dogs).

STRAY NOTES

While it’s true that some premises are only discovered in the course of writing and revising, you should still start your script with at least an inkling of what the main character is going to spend the most time doing. If you have trouble doing this in the preliminary stages, you’re going to have even more trouble doing it after you’ve spent three months committing to a draft.